Attach rigid bodies to rigged mesh
I've done.

Youtube:



First of all - seems that rigid bodies aren't working with armature-deformed meshes directly. But with some intermediate objects it is possible to make them. I made the chain: rigid proxy object ("fake tip") and ball constrainted by empty ("joint"), this empty is child of "fake tip", "fake tip" is child of last bone in armature. Also armature constrainted with IK and deforms mesh ("tentacle"). 

Looks like you have to place additional rigid proxy objects for every bone where could be collision with other rigid bodies.

I made some different attempts with different combinations and only this one works for me. But hope somebody could make it simplier.

Added some screenshot: